Irritated... Why?

I forgot to tell you on my previous post that I woke up really early today. Around 4:50 am, I suppose. Upon my arrival at school this morning, I immediately went to the library to borrow a management book. I asked the library's staff, Ms. Rona, if they have the book I previously mentioned on my previous post. She said that it's already out. then, as I was making my way out of the library, I remembered that I need to borrow the "official reviewer of the Quiz Bee" which is "Answerboards Up!" by Ms. Pettizou Tayag, the competition's quizmaster. I asked Ms. Rona if they have it. She told me that it isn't in the library. I insisted that it is indeed in the library since I was the last person who borrowed it (indirectly). She was irritated as her actions implied.
Then, Ate Lovelyn, an orgmate didn't even greeted me when she saw me. The same to a professor of mine. Why are you people irritated and snobbish? I wonder why. Have a great day ahead!